Split-chamber pressure exchangers

ABSTRACT

The invention relates to split-chamber pressure exchangers. Split-chamber pressure exchangers are characterized in that the pressure exchange chambers and the pistons thereof are split in two. Each fluid passes through the corresponding chamber thereof, such that said fluids cannot be mixed. The cross sections of the chambers can be varied in order to vary the transmitted pressure. The reverse line operation can be established and synchronized using a U-shaped tube with telescopic sides and a fixed base filled with fluid or diametrically opposed curved lines, and multiple arrangements can be used. Split-chamber pressure exchangers can be used as surface or well pumping systems and the pumping fluid used can differ from the fluid to be pumped. Different levels of any material can be exploited at any storage site using a chamber with elastic walls filled with fluid and attached to the bottom. Electric power can be generated by centrifuging the pre-pumped fluid.

FIELD OF THE ART

The invention is comprised within the field of pressure exchangers,which are for transmitting dynamic pressure from one fluid to anotherdifferent fluid.

Due to the innovations provided, the invention is transformed into a newpumping system for any type of fluids, and even into a new electricpower generation system.

STATE OF THE ART Pressure Exchangers

Pressure exchangers were invented over more than twenty-five years agoand they basically consist of pressurizing one fluid (fluid 1 in FIG. 1)from the pressure of another fluid, which is depressurized after theprocess (fluid 2). There are several models, but they all basically workaccording to the diagram of FIG. 1. The fluid 1 is introduced in theinterconnecting chambers by means of a system of shut-off and checkvalves, represented by the gray boxes. Once filled, the fluid 2 isallowed to pass through the other end, displacing said fluid by pushingan transmitting intermediate member which transmits the residualpressure between them, separating them (usually a disc or piston, thoughoccasionally an intermediate fluid or any other system is used). Thefluid 1 is thus pressurized. Then the inlet of the fluid 2 is shut offand a discharge valve opens. The fluid 1 is again allowed to passthrough by means of the valve system, displacing fluid 2 (which now doesnot have pressure), discharging it through the drain.

The system is assembled with two parallel interconnecting lines and iselectronically controlled such that at all times the disc or piston ofeach tube is located in the opposite position with regard to the center(reverse line operation) to thus achieve the most constant pressurepossible at the outlet of the fluid 1, and to likewise achieve thegreatest possible exploitation of the pressure of the fluid 2.

FIG. 1 shows the fluids 1 and 2 using lighter shades when they do nothave pressure and darker shades when they are pressurized. Thesedifferent shades will be maintained throughout all the figures attachedto this description.

A thorough worldwide search has been conducted in the espacenet databasefor patent documents relating to pressure exchangers, and it has beenfound that although there has been considerable development thereof,none of them provide the innovations described herein.

Current Applications of Pressure Exchangers

Pressure exchangers have traditionally been used in mining to displaceresidual processing water with clean water and the system is usedwithout discs or pistons since it does not matter if both fluids mix.

They are starting to be used today in reverse osmosis water desalinationplants according to a scheme such as that depicted in FIG. 2. Theprocess is very simple: it pre-treats the water and then raises thepressure of the water until it exceeds its osmotic pressure. The wateris then passed through reverse osmosis filters which have asemi-permeable membrane and produce two outputs: desalinated anddepressurized water on one side and brine at a fairly high pressure onthe other side. This pressure is used to pressurize part of the watercoming from the pre-treatment, thus reducing the output of high pressurepumps with the subsequent electric power savings.

Pumping Systems

Many types of horizontal, vertical and submerged electric pump units forclean water have been extensively developed to date, as have manypumping systems for all types of fluids (waste water, viscous fluids,toxic fluids, hazardous fluids, seawater, chemicals, concrete, turbidwater, or any type of fluid imaginable, including fluids with solids insuspension).

EXPLANATION OF THE INVENTION

Technical Problems Involved with Traditional Pressure Exchangers

Although the system proposed in the previous section relating todesalination is fairly energetically efficient, it presents twoproblems:

-   -   the outlet pressure of the reverse osmosis filters of the brine        is always lower than that of the feed water, which means that it        is necessary to install a booster pump increasing the pressure        of the water    -   since the pre-treatment water and the brine are separated in the        pressure-transmitting intermediate members, there is always a        small though significant mixture of both fluids, therefore the        pre-treatment water leaves the pressure exchangers with a higher        salt concentration, which obviously jeopardizes the process

Furthermore, traditional pressure exchangers generally present anotherdrawback, which is that the fluid to be pressurized (fluid 1) is forcedto displace the fluid 2 once it has been depressurized. This is not somuch of a problem in the case of desalinators because the water to bepressurized comes from the pre-treatment process, from which it leaveswith some pressure, but in other applications it may be a seriousdrawback, especially taking into account the fact that the reverse lineoperation is necessary, and the natural speeds of the discs or pistonsin either direction are very different. This reduces the performance ofthe exchangers and complicates the system control electronics.

All these drawbacks are probably what have not allowed furtherdevelopment of pressure exchangers in all types of applications.

Technical Problems Involved with Traditional Electric Pump Units

Even though the designs of all types of electric pump units are welloptimized today, they have some shortcomings which until now have beenimpossible to solve, such as:

-   -   regarding electric pump units for removing water from wells or        collection boxes, the motor of vertical units is on the surface,        but they cause many mechanical problems with the long shaft they        require, and submerged units have the problem that since the        pump body and the motor are submerged in the well or collection        box, any operating failure causes the unit to be out of service        for a considerable time period since the unit must be        disassembled and then assembled    -   regarding the pumping systems for other fluids, they have a        lower performance in many cases and usually offer many        maintenance problems due to the inlet of solids, such as the        case of waste water pumping, or due to corrosion of the delicate        and expensive pump body, or due to both effects

GENERAL DESCRIPTION OF THE INVENTION AND SOLUTIONS PROVIDEDSplit-Chamber Pressure Exchangers (SCPEs)

These are pressure exchangers characterized in that the pressureexchange chambers are split in two, one for each of the fluids, as shownin FIG. 3. Each of the fluids therefore only passes through thecorresponding chamber thereof, such that said fluids cannot be mixed(and the second problem described in the preceding section is thereforesolved).

The exchange of pressures takes place by replacing thepressure-transmitting intermediate members in traditional with tworigidly attached discs or pistons, as shown in FIG. 3. The pressurizedfluid will thus push and also displace the other fluid through thecorresponding chamber thereof. The chambers obviously need to have anopening to the outside to allow the inlet and outlet of air during themovements of the discs or pistons and to prevent vacuums, as can also beseen in FIG. 3.

Drains can be arranged at the opposite ends of the chambers in case itis necessary to drain a small amount of the fluids which may be lostthrough the disc or piston seals.

Arrangements

SCPEs with Piston-Type Chambers

A first possible arrangement would be the one shown in FIG. 3, in whichthe cross sections of each chamber are identical. The same pressurewould thus be transmitted from the pressurized fluid to the fluid to bepressurized, except obviously mechanical losses.

The inventive system allows another arrangement, in which the crosssections of the chambers are different (FIG. 4), and therefore thetransmitted pressure is also different (the pressure ratio will be equalto the area ratio, except obviously for mechanical losses, since the netforce is the same). The problem of the need for the booster pumpmentioned above in the description of the technical problem involved canthus obviously be solved.

Obviously, the vertical or angled arrangement of the lines is possible(FIG. 5), but this will worsen the problem that the fluid to bepressurized (fluid 1) must displace the fluid 2 once it has beendepressurized, since in this case it must also overcome the weight ofthe fluid, plus that of the discs or pistons and the attachment betweenthem. To that end an additional lifting system thereof could also bearranged, the control of which would be integrated in the electroniccontrol system of the system, or the drain system shown in FIG. 6 can beused, which consists of exploiting the energy from the pressurized fluid(fluid 2) not only to transmit it to the fluid to be pressurized (fluid1), but also to aid the actual fluid 1 in displacing fluid 2 in theother line once it has been depressurized. This is achieved by means ofan auxiliary U-shaped tube which interconnects both lines as shown inFIG. 6, and it is a telescopic tube on both sides of the “U”, beingrigidly supported by the base of the “U”. The ends of the “U” areattached to the discs or pistons of their respective lines, and the “U”is filled with an incompressible fluid. Therefore, when the fluid 2under pressure enters its chamber, not only does it apply pressure toits disc or piston to displace fluid 1, but it also transmits part ofits energy to the disc or piston of the other line to aid fluid 1 of theother line in displacing the depressurized fluid 2 in said line and inovercoming the friction of the discs or pistons and their weight andthat of the depressurized fluid 2 if necessary. Logically, the crosssection of the tube must be such that the energy transferred to the discor piston of the other line is the necessary minimum. The reverse lineoperation is furthermore assured by means of this system, thussimplifying the system control electronics. It can be assembled in anytype of pressure exchangers, whether they are split chambers or not.Obviously, instead of being a telescopic tube they could be severaltelescopic tubes equidistant from one another and from the center, or aring made up of several sections of the same length and equidistant forthe purpose of better distributing the stress on the discs or pistons.

Finally, curved or circular chamber lines can also be arranged, in whichcase the attachment between the discs or pistons will be curved and havethe same radius, and will be attached to the center by means of aball-type joint (FIG. 7). An increase of the pressure transmitted canthus be achieved depending on the distance of the chambers of bothfluids to the center, without needing to change the cross section of thechambers, though without jeopardizing the possibility of being able tocombine both effects. Furthermore, if the two lines are placeddiametrically opposed to one another, and the attachment parts betweenthe discs or pistons of each line are in turn rigidly attached to oneanother, as shown in FIG. 7, the same effect is achieved as with thepreviously described U-shaped part, i.e., on one hand the reverse lineoperation is achieved, thus simplifying the system control electronics,and on the other hand the fluid 2, once it is depressurized, isdisplaced from the corresponding chambers thereof without needingauxiliary pumping, in cases in which the fluid 1 enters under verylittle pressure.

The splitting of chambers can be applied to all types of traditionalpressure exchangers developed today. There particularly exists anothertype of traditional pressure exchangers, which are mentioned perhapsbecause they are the most distinguished of all of them, which are basedon the same operating principle but consisting of a cylinder with aseries of inner conduits through which the fluids pass, the pressuresbeing exchanged. They further have the particularity that the actualcylinder rotates about its own axis. The chambers of this type ofexchanger can also be split to obtain the advantages herein explained.

SCPEs with Telescopic Chambers

These are SCPEs in which in order to transmit pressures the chambers aretelescopic and push one another, rather than the rigidly attached doubledisc or piston system. FIG. 8 shows a schematic depiction thereof.

SCPEs with Bellows-Type Chambers

These are SCPEs in which in order to transmit pressures the chambers arebellows-type chambers and push one another, rather than the rigidlyattached double disc or piston system. FIG. 9 shows a schematicdepiction thereof.

SCPEs with Membrane-Type Chambers

These are SCPEs in which the chambers in each line are arranged suchthat those corresponding to the fluid to be pressurized have rigidwalls, and those of the fluid which yields its pressure aremembrane-type chambers, the latter being included within the rigid walltype. FIG. 10 shows a schematic depiction thereof.

SCPEs with Mixed Chambers

Obviously any of the possible arrangements (piston-type, telescopic,bellows-type or membrane-type) can be combined such that the chamberscorresponding to one of the fluids can have one arrangement and thechamber corresponding to the other fluid can have a differentarrangement.

Two of the possible combinations are depicted in FIGS. 11 (piston-typechambers/telescopic chambers) and 12 (telescopic chambers/bellows-typechambers).

Multistage SCPEs

Multistage SCPEs consist of the splitting the chambers of the fluid thepressure of which is yielded into several chambers, which may or may notbe used depending on the available pressure of the fluid, by means of avalve system, thus being able to transmit the most homogenous pressurepossible to the fluid to be pressurized, as shown in FIG. 13.

They can also be arranged such that the chambers which are split are thechamber of the fluid to be pressurized, thus pressurizing it atdifferent pressures depending on the needs at all times.

By means of the aid of an auxiliary tank, all the chambers can be filledcontinuously so as to allow opening auxiliary chambers midway through ifthe feed pressure changes, maximally exploiting the energy of thepressurized fluid, as shown in FIG. 14.

Both FIGS. 13 and 14 depict multistage SCPEs with piston-type chambers,but they can obviously also be provided with telescopic, bellows-type,membrane-type or mixed chambers. They are further depicted with thedifferent chambers by way of concentric and overlapping cylinders, butthey can obviously be arranged with any possible geometry provided thatthe pressurized fluid pushes through all the chambers in the samedirection.

FIG. 15 depicts a multistage SCPE with a circular arrangement, whichallows the aided reverse operation, as explained above. For thoseapplications in which either the pressure at which the fluid thepressure of which is yielded must be returned once it has beendepressurized, or the starting pressure of the fluid to be pressurizedis variable, or both, with multistage SCPEs with a circular arrangement,or with other arrangements and the U-shaped tube system also describedabove, the control system can adjust the stages that must startoperating also depending on these pressures.

Finally, it is also possible to complement the system with auxiliarypumping and a speed variator to keep the pressure of the fluid to bepressurized completely constant, controlling all this from theelectronic control system. If the pressurized fluid comes from pumping,the speed variator can be placed in said pumping.

Variable Section SCPEs (VSSCPEs)

Another interesting possibility regarding the design of SCPEs rests ontheir being able to have a variable section in any of the fluid chambersthereof fluid (one, several or all). To that end, it is essential forthe piston, the actual chambers, or both, to be able to have variablesections. Both possibilities are described below.

Variable Section Pistons

These are pistons which have a section that changes along the pistonstroke. To that end, the chamber on which they are housed must have avariable cross section.

The pistons must be designed such that their section can increase ordecrease, maintaining their own rigidity and the seal of theirattachments with the walls of the corresponding chamber thereof. To thatend, any type of mechanical or pneumatic system, or a combinationthereof, can be used.

FIGS. 16 and 17 depict the starts and the ends of the stroke of avariable section piston. For the sake of simplicity, a piston-typeexchanger with a single line has been considered.

Since the section of the piston gradually reduces, the pressure exertedon the fluid to be pressurized increases.

This type of VSSCPE can be applied in those situations in which thedistribution of pressures required by the system is known beforehand.

Variable Wall Chambers

The distribution of pressures required by the system at all times isgenerally not known a priori in most of the possible applications, andthe purpose is to attempt to modulate it depending on the needs of theactual system.

Variable geometry chambers, either telescopic or piston-type chambers,can be used in these cases, which can open or close and even open at oneend and close at the other. FIGS. 18 and 19 depict a single-linepiston-type VSSCPE with one of its chambers being a variable sectionchamber.

Any type of mechanical or pneumatic system can be used to move the wallsof the variable section chambers. The use of auxiliary telescopiccylinders which are filled with an incompressible fluid and fixed at oneend to the wall of the chamber and at the other end to a fixed wall, asshown in FIGS. 18 and 19, may be particularly interesting. The walls ofthe chamber are moved by extracting fluid from or introducing fluid intothe cylinders according to the needs of the system.

Telescopic cylinders could obviously be replaced with a fixed chamberfilled with an auxiliary fluid on which the actual wall of the chamberof the VSSCPE would move like a piston (FIGS. 20 and 21).

As explained above, it is also possible to provide chambers such thatthey can open at one end and close at the other end or vice versa (FIGS.22 and 23).

It is important to point out that the walls of the chambers can movewith very little force while the corresponding chamber is not loaded,therefore this would be the ideal time to do it. However, in certainapplications it may be of interest to move them during the stroke of thepiston, when the chamber is loaded, though to that end it is necessaryto exert a greater force.

Finally, the possibility of using a membrane or elastic material so thata telescopic chamber opens or closes for the purpose of preventing theneed for the piston to have a variable section (FIGS. 24 and 25) shouldalso be mentioned.

Control of the Speed of the Piston

An additional advantage of considerable interest is that the VSSCPE canbe designed such that the speed of the piston is constant, except in asmall initial span in which it must be accelerated to the desired speed.The energy transfer performance is thus optimized since it is not usedfor an unnecessary acceleration of the double or single disc or piston.FIG. 26 depicts a possible design for this purpose, which consists ofproviding the chamber with one of the fluids of an initial variablesection span, during which the piston accelerates until reaching thedesign speed, at which time the straight span is reached, and the speedis kept constant since the system is designed so that at that time theforce exerted on the piston by the fluid the pressure of which isyielded is equal to the force exerted by the fluid to be pressurizedthereon plus losses due to friction corresponding to the design speed.

There is another way to design it to keep the speed of the pistonconstant which is explained in FIGS. 27 and 28, and it prevents thepiston from having to be a variable section piston. As can be seen, thechamber has a section step, and again it is designed to reach thedesired speed of the piston in the initial span with a larger section.In this case, the piston would have the possibility of being separatedinto two or more parts, such that during the first span it is keptrigidly attached and during the second span it separates. This could bedone with any type of mechanical system.

Obviously, it is also possible to provide systems in which the initialacceleration of the piston is done by means of any other mechanical,electric, magnetic or pneumatic system imaginable, and even systems inwhich the piston accelerates while the gas is entering the chamber, suchthat the pressure to overcome is minimal.

Batteries of Exchangers

As occurs with traditional pressure exchangers, SCPEs having any of thepresented arrangements can be arranged in series (FIG. 29), or inparallel (FIG. 30). Likewise, when the pressure surges which are soughtare very high, mixed systems with pumps can be arranged to increase thepressure of the pressurized fluid and/or the pressure of the fluid to bepressurized at the inlet and/or at the outlet of the pressure exchanger(FIG. 31), without jeopardizing the fact that they can also be arrangedin series or in parallel.

Control Electronics

Regarding the control electronics of the valves, a card with a processorcan be assembled in situ, or signals can be sent to a central computercontrolling them. In the case of multistage SCPEs, the control systemwill be more complex as it must regulate the valves depending on theinlet and/or outlet pressures of the two fluids involved.

Number of Lines per SCPE

Regarding the number of lines necessary per SCPE, there will usually beat least two in number but depending on the ranges of outputs andpressures worked with in each case, it may be appropriate to increasethe number to three or more lines, although it may be appropriate for aline to not have the same length, since it would be used to achieve themost constant outlet pressure possible of the starting pressurizedfluid.

In addition, on certain occasions it may be appropriate for only oneline to be arranged, considerably simplifying the system controlelectronics.

Geometry of the Chambers

Finally, regarding the geometry of the lines of the chambers, in any ofthe longitudinal arrangements they can be straight, curved and evencircular, and the cross section thereof may be circular, elliptical,triangular, square, rectangular, polygonal or any imaginable crosssection.

Alignment

Finally, the SCPEs in any of the arrangements put forth can be alignedin any possible way (horizontally, vertically or angled). FIGS. 32 and33 show multistage SCPEs with vertical alignments, with the pressurizedfluid pushing upwardly (FIG. 32) or downwardly (FIG. 33).

Design of the Attachments in Piston-Type SCPEs

To reduce the effect of the bending stresses in piston-type SCPEs,another possibility consists of reinforcing the attachments of the rod,rods, sheets or central solid parts with the discs or pistons, as shownin FIGS. 34 and 35.

Advantages of the Invention Over the Prior State of the Art

As explained above in the general description of the invention, theessential advantages of the SCPEs are the following:

-   -   each of the fluids only passes through the corresponding chamber        thereof, such that said fluids cannot be mixed. This means that        this system can be used to pump any type of fluid transmitting        the necessary energy to another different fluid (which can be        clean water, and even distilled water, or any other fluid that        is found to cause less damage to the electric pump units), and        then exchanging the pressures thereof. Very heavy and        non-corrosive fluids can also be chosen to reduce the size of        the pumping and storage installations. This will entail an        increase of the performance achieved as well as a considerable        savings in maintenance costs and even in installation design and        execution costs    -   they allow changing the cross sections of the chambers, thus        changing the pressure transmitted to the fluid to be        pressurized. This is another considerable advantage of this        invention, since it allows choosing between pumping a greater        output at a lower height, or a lower output at a greater height,        which makes it possible to choose in each case the type of pump        offering the best performance and better exploiting small        pressure differences or small level differences of large amounts        of fluid, as will be described below    -   they allow assuring and harmonizing aided reverse line        operation, either by means of the U-shaped tube with telescopic        sides and fixed base filled with incompressible fluid or by        means of the arrangement of diametrically opposed curved lines,        and attachment parts between pistons of each line rigidly        attached to one another    -   they allow exploiting the energy of the level differences of any        material in any storage form by means of the also innovative        method described below, and furthermore,    -   SCPEs with telescopic, bellows-type, membrane-type or mixed        chambers prevent the problem of bending stresses occurring in        the discs or pistons rigidly attached to one another, reduce the        space that the chambers occupy by half, and can be designed so        that the reverse operation does not have to be aided, since it        is possible to play with the elasticity of the membranes or        design telescopic or bellows chambers such that they always        automatically return to their starting position with enough        force to drag the fluid, once depressurized, therein    -   multistage SCPEs transmit the most homogenous pressure possible        to the fluid to be pressurized, despite the variations of the        pressure of the pressurized fluid at the inlet, or they        pressurize it at different pressures depending on the needs at        all times    -   for those applications in which either the pressure at which the        fluid the pressure of which is yielded must be returned once it        has been depressurized, or the starting pressure of the fluid to        be pressurized is variable, or both, with multistage SCPEs with        a circular arrangement, or with other arrangements and the        U-shaped tube system, the control system can adjust the stages        that must start operating also depending on these pressures    -   in piston-type SCPEs, the reinforcement of the attachments of        the rod, rods, sheets or central solid parts with the discs or        pistons reduces the problem of bending stresses    -   VSSCPEs open up the possibility of modulating the working        pressures of split-chamber pressure exchangers, which will allow        better adapting to the needs of a large amount of possible        applications    -   an additional advantage that is of considerable interest is that        VSSCPEs can be designed such that the speed of the piston is        constant, except in a small initial span in which it must be        accelerated to the desired speed. The energy transfer        performance is thus optimized since it is not used for an        unnecessary acceleration of the double or single disc or piston.

DESCRIPTION OF THE DRAWINGS

Fifty drawings are attached to aid in explaining the operation,arrangements and applications of SCPEs. Reference is made thereto fromseveral different points of this document, explaining in each case thecontent thereof. In any case, the relation and content of each drawingis provided below:

FIG. 1: Diagram of traditional pressure exchangers

FIG. 2: Process of a desalination plant with traditional pressureexchangers

FIG. 3: Diagram of a split-chamber pressure exchanger

FIG. 4: SCPEs with different cross sections

FIG. 5: Vertical assembly of SCPEs

FIG. 6: Aided reverse operation of SCPEs

FIG. 7: Assembly of SCPEs with curved lines

FIG. 8: SCPEs with telescopic chambers

FIG. 9: SCPEs with bellows-type chambers

FIG. 10: SCPEs with membrane-type chambers

FIG. 11: SCPEs with mixed chambers (piston-type/telescopic)

FIG. 12: SCPEs with mixed chambers (telescopic/bellows-type)

FIG. 13: multistage SCPEs

FIG. 14: multistage SCPEs with auxiliary tank

FIG. 15: multistage SCPEs with circular arrangement

FIG. 16: Diagram of a line of a piston-type VSSCPE with a fixed sectionchamber and the other chamber being a variable section chamber withfixed walls, the stroke of the piston starting

FIG. 17: Diagram of a line of a piston-type VSSCPE with a fixed sectionchamber and the other chamber being a variable section chamber withfixed walls, the stroke of the piston ending

FIG. 18: Diagram of a line of an immobile wall VSSCPE with telescopicpneumatic cylinders for securing the walls, the stroke of the pistonstarting

FIG. 19: Diagram of a line of an immobile wall VSSCPE with telescopicpneumatic cylinders for securing the walls, the stroke of the pistonending and after having modified the section of the immobile wallchamber

FIG. 20: Diagram of a line of an immobile wall VSSCPE with an outerchamber filled with fluid for securing the walls, the stroke of thepiston starting

FIG. 21: Diagram of a line of an immobile wall VSSCPE with an outerchamber filled with fluid for securing the walls, the stroke of thepiston ending and after having modified the section of the immobile wallchamber

FIG. 22: Diagram of a line of an immobile wall VSSCPE with twotelescopic pneumatic cylinders for securing the walls, which allow themovement and the rotation of the walls of one of the chambers, thestroke of the piston starting

FIG. 23: Diagram of a line of an immobile wall VSSCPE with twotelescopic pneumatic cylinders for securing the walls, which allow themovement and the rotation of the walls of one of the chambers, thestroke of the piston ending and after having modified the geometry ofthe immobile wall chamber

FIG. 24: Diagram of a line of an immobile wall VSSCPE with telescopicpneumatic cylinders for securing the walls, fixed section pistons andelastic span in the immobile wall chamber, the stroke of the pistonstarting

FIG. 25: Diagram of a line of an immobile wall VSSCPE with telescopicpneumatic cylinders for securing the walls, fixed section pistons andelastic span in the immobile wall chamber, the stroke of the pistonending and after having modified the section of the immobile wallchamber

FIG. 26: Diagram of a line of a VSSCPE in which one of the chambers hasan initial variable section span to accelerate the piston

FIG. 27: Diagram of a line of a VSSCPE in which one of the chambers hasan initial smaller section span to accelerate the piston during thepiston acceleration phase

FIG. 28: Diagram of a line of a VSSCPE in which one of the chambers hasan initial smaller section span to accelerate the piston during theconstant piston speed phase once the two parts of the piston are set

FIG. 29: Assembly in series of the SCPEs

FIG. 30: Assembly in parallel of the SCPEs

FIG. 31: Mixed systems of electric pump units and SCPEs

FIG. 32: Multistage SCPEs in vertical arrangement, with the pressurizedfluid pushing upwardly

FIG. 33: multistage SCPEs in vertical arrangement, with the pressurizedfluid pushing downwardly

FIG. 34: Reinforcements in the attachments of the rod, rods, sheets orcentral solid parts with the discs or pistons (I)

FIG. 35: Reinforcements in the attachments of the rod, rods, sheets orcentral solid parts with the discs or pistons (II)

FIG. 36: Step-wise operation of the multistage SCPE (I)

FIG. 37: Step-wise operation of the multistage SCPE (II)

FIG. 38: Step-wise operation of the multistage SCPE (III)

FIG. 39: Step-wise operation of the multistage SCPE (IV)

FIG. 40: Pumping system with SCPEs

FIG. 41: Pumping system for wells or collection boxes with SCPEs

FIG. 42: Exploitation of the geographic level differences of a river

FIG. 43: Exploitation of the level difference of tides (high tide)

FIG. 44: Exploitation of the level difference of tides (low tide)

FIG. 45: Exploitation of the level difference of tides with an elasticwall chamber (high tide discharging fluid from the chamber)

FIG. 46: Exploitation of the level difference of tides with an elasticwall chamber (high tide when the discharge of fluid from the chamberends)

FIG. 47: Exploitation of the level difference of tides with an elasticwall chamber (low tide loading of fluid into the chamber starts)

FIG. 48: Exploitation of the level difference of tides with an elasticwall chamber (low tide loading fluid into the chamber ends)

FIG. 49: Exploitation of the level difference of tides with an elasticwall chamber and continuous feed system

FIG. 50: Process of a desalination plant with SCPEs

DETAILED EXPLANATION OF AN EMBODIMENT OF THE INVENTION

FIGS. 36 to 39 diagrammatically depict the operating process of amultistage SCPE, with seven concentric chambers located on the side ofthe pressurized feed fluid.

FIG. 36 shows the first of the lines starting to be filled and thesecond one starting to drain. The pressure gage at the inlet of thepressurized fluid records a high pressure of the fluid, therefore thevalve feeding the concentric chambers closes and therefore onlypressurized fluid enters the central cylinder. The valve system in thegray box in the figure allows the passage of pressurized fluid to thefirst line and prevents the passage thereof to the second line.Likewise, said system allows draining said already depressurized fluidfrom the second line. In addition, since the valve feeding theconcentric chambers in the valve system shown in the figure in thesecond line is closed, it allows draining the fluid from the centralcylinder but not from the remaining cylinders. The fluid contained inthe remaining cylinders therefore exits through the conduit leading itto the auxiliary tank.

The system therefore works by raising the fluid of the first line andlowering the fluid of the second line. The auxiliary tank furthermorefeeds the concentric cylinders of the first line, since the valvesgiving access to each of them open. The level in the auxiliary tank doesnot drop, since it is in turn fed by the depressurized fluid of theconcentric cylinders of the second line. For this reason such tank couldeven be eliminated and converted into a flow-off.

At a certain time, the lines work up to a mid point as depicted in FIG.37. At said time, the pressure gage detects a drop in the pressure ofthe pressurized feed fluid, and for this reason the control systemimmediately calculates how many chambers must start working in order tokeep the pressure transmitted to the fluid to be pressurized as constantas possible depending on said drop. In the case that is shown, thecontrol system would activate four of the concentric cylinders, as shownin FIG. 38. Obviously, since the concentric cylinders are filled withfluid depressurized coming from the auxiliary tank, these cylinders areautomatically pressurized with the single opening and closing of thecorresponding valves, the fluid therefore not losing energy while itfills the concentric cylinders if they are empty.

After this time, since the concentric cylinders of the second linecontinue discharging into the auxiliary tank and the latter only feedsthe remaining ones of the first line, the tank starts to fill andtherefore overflow through the spillway, discharging the fluid into thecorresponding drain, as shown in FIG. 39, in which the lines are assumedto be reaching the end of their stroke.

Once the end of the stroke has been reached, it is necessary to startdischarging the first line and loading the second line according to aprocess similar to that herein shown.

The process is repeated indefinitely

INDUSTRIAL APPLICATIONS OF THE INVENTION

Due to the described important advantages provided by the invention, therange of industrial applications opened up is very wide. The mostrelevant ones are listed below:

1) As a pumping system in general (FIG. 40), since it has the followingadvantages as it has split chambers:

the fluid which is used to pump (fluid 2 in FIG. 40) does not have to bethe same as that to be pumped (fluid 1), which is extremely importantand applicable in infinite cases. In other words, whether dealing withwastewater, viscous fluids, toxic fluids, hazardous fluids, seawater,chemical products, concrete, turbid water or any type of fluidimaginable, even fluids with solids in suspension, clean water pumps andeven pumps working with distilled water or any other fluid which hasbeen proven to damage the electric pump units less can be used withexchangers of this type (very heavy and non-corrosive fluids can bechosen to reduce the size of the pumping and storage installations).This will involve an increase of the performances achieved as well asenormous savings in the maintenance and even design and execution of theinstallations

a choice can be made between pumping greater output at a lower height,or a lower output at a greater height; the type of pump giving a betterperformance can thus be chosen in each case. Furthermore, this enablesexploiting in a much better manner small pressure differences or smalllevel differences of large amounts of fluid

2) in hydroelectric power stations, by inserting these SCPEs a choicecan also be made between centrifuging greater output at a lower height,or a lower output at a greater height, which allows choosing in eachcase the type of turbine giving a better performance. Obviously, and ashas been forth in the previous point, the fluid to be centrifuged doesnot have to be the same, which also involves another important advantagesince fluids can again be chosen in a customized manner to reduce themanufacture and maintenance costs of power stations

3) regarding submersed or vertical pumps in wells or deep collectionboxes, they can be replaced with surface pumps with SCPEs having longattachments between the discs of the order of the length of the well orcollection box, such that some chambers are located on the surface andother at the bottom of the well or collection box (FIG. 41). Thechambers of the surface are fed with any fluid, again chosen to optimizethe manufacture and maintenance costs of the installations. This systemcan be assembled in two stages, such that in the first stage the wateror fluid to be pumped is raised to the surface and in the second stageits pressure is raised to the desired pressure. The system can also beassembled with the lower chambers of the SCPE in dry conditions, eitherin the same well or collection box above the water level, using a smallauxiliary feed pumping, or in a contiguous tight collection box

4) the natural level differences of a river can also be exploited,placing the SCPEs in one of the banks of the river at a certain depth,which SPCEs are feed from an intake coming from the river, and byplaying with the sections of the chambers the pressure of the fluid tobe pumped (water from the river itself for irrigators, country estates,housing developments, municipalities or nearby industries, or any otherfluid to be pumped for any type of process) is raised. The water of theriver enters one of the chambers of the SCPEs with a certain pressuredue to the depth at which the SCPEs are placed and/or to a prior feedpumping. Furthermore, by suitably placing the intake, the kinetic energyof the river current can also be exploited. At the outlet, this water isagain discharged into the river through a conduit which moves itdownstream such that it falls by gravity or at least the height to bepumped is reduced (FIG. 42). If there is enough geographic leveldifference, a turbine can also be placed to exploit the residual energyof the water prior to returning it to the river bed

5) another application consists of exploiting the level differencecaused in seas, rivers and river mouths by tides. Water can be takendirectly from the sea or from a beach well when the tide is high and,after pumping it if necessary or driving it downwardly to increase itspressure, it feeds the SCPEs, and it is then stored in a basin or tank(FIG. 43) in order to wait until the tide ebbs and it is then returnedto the sea by means of a pumping if necessary, which will be providedwith a check valve at the outlet to prevent the water from circulatingin a reverse direction when the tide is high (FIG. 44). While the tideis low, if the plant is to be kept operating, it will be necessary topump or pump with a higher surge the feed water of the exchangers. Tooptimize the system, two pumps can be assembled in parallel or a pumpcan be assembled in parallel with a simple tube, according to the designneeds

6) another way to exploit the level difference of the tides consists ofusing a fluid installed inside a chamber with elastic walls(membrane-type chamber). The chamber is placed inside the sea firmlyattached by its base to the seabed, as shown in FIGS. 45 to 48. A pipeextending to solid ground emerges from the bottom of the chamber, whichpipe has a shut-off valve. While the tide rises, the chamber is filledwith the fluid and with the shut-off valve closed, such that thepressure of the fluid increases. When the tide is high, the shut-offvalve opens and the chamber starts to be drained, feeding the SCPEs(FIG. 45). If necessary, an additional pumping prior to the inlet to theexchangers would be added, as shown in FIG. 45. The process continuesuntil the chamber is completely drained (FIG. 46). The depressurizedfluid at the outlet of the exchangers has been stored in a basin ortank, to discharge it or pump it again to the chamber when the tide ebbs(FIG. 47), until the chamber is filled again (FIG. 48). If it isnecessary to work continuously, the exchangers can be fed the rest ofthe time by means of pumping from the fluid storage basin or tank (FIG.49). A very heavy fluid can be chosen to optimize the dimensions of thesystem, or even the seawater itself or any other fluid, such as freshwater or even distilled water can be used to reduce the wear with theuse of the installation. It is also important to emphasize theenvironmental advantage of this system compared to other developedsystems for exploiting the level difference caused by tides (whichnormally involves constructing dams or other works with a considerableenvironmental impact), as the environmental impact is zero since thechamber with elastic walls is submersed. To end this point, it mustsimply be added that rigid but telescopic walls, or rigid walls with theupper part moving upwardly and downwardly like a piston rather thanelastic walls could be placed

7) obviously the system for exploiting the level differences caused bytides with the system of a chamber with elastic walls set forth in theprevious application could be extrapolated to any other level differenceoccurring over time of any type of material imaginable, whatever thestate in which it is, as is the case of reservoirs, tanks for drinkingwater, irrigation water or for any other fluid in any type of industrialprocess, and even any type of silo, tank or place in which solids arestored or pooled, since, in short, what this system does is exploit thefact that in a certain place there is something which is loaded andunloaded over time and the weight of which is exploited to press a fluidfeeding the SCPEs. It will occasionally be suitable for the fluid to beused to be a gas so that it occupies less when it is compressed andstorage capacity is not lost. The system can be electronicallycontrolled by means of a computer to optimize the times in which thepressure of the fluid inside the chamber is exploited, since in manycases the levels do not change from maximum to minimum and vice versa,and therefore it may be suitable to exploit the turning points frombeing filled to being drained and vice versa

8) The geographic levels existing in sanitation networks and especiallyrainwater networks can also be exploited, because since the latter caseinvolves clean (rain) water, it is easier to handle as a fluid forfeeding the SCPEs. The mode of operation is similar to that describedfor rivers, i.e., an intake is made at a point of the network whichfeeds the exchangers, which are at a lower level to achieve a certainpressure at the inlet, and, once used to increase the pressure of theother fluid (any fluid which is to be pumped), it is again dischargedinto the network downstream, either completely by gravity or with theaid of a pumping

9) the residual pressure of multiple fluids involved in industrialprocesses, and generally any imaginable residual pressure can besimilarly exploited with this system

10) another very important application is that relating to fluiddistribution networks. The two probably most important cases aredrinking water and irrigation water distribution networks. Generally, ina distribution network, the fluid is introduced at one or severalpoints, and there are multiple outlets throughout it. However a minimumpressure is to be arranged at the most unfavorable point of the network,in many spans of the network there are overpressures which sometimeseven force placing pressure-reducing valves. Furthermore, the outputcirculating at the start of the distribution of the network does notneed to be complete for the first supplies, but rather it could verywell be considerably reduced such that only that necessary one remainsto attend to said first supplies. Thus, by means of the correspondingpipe network, a part of the fluid could be collected at the start of thenetwork, it could be used to feed SCPEs, and finally it could bereturned to the distribution network, downstream and with less pressure,particularly with the pressure necessary at that point of the network.The fluid which is placed on the side of the exchangers, which can bethe fluid itself of the network to supply high points thereof or theheader tanks, or any other fluid which it is necessary to pump (forexample, wastewater in the case of drinking water distribution networks)is thus pressurized

11) any possible combination of the described applications; for example,by means of an integrated control of the system, seawater desalinationplants could well use a combination for exploiting the level differencesof tides, the level differences of a possible river running or openingout close to the location of the plant, nearby drinking water orirrigation water distribution networks, sanitation and/or rainwaternetworks, or any other fluid with residual pressure in any type ofindustrial process existing in the area. FIG. 50 depicts the diagram ofa seawater desalination plant with SCPEs (which obviously alsocorresponds to that of a brackish water desalinator but without theadvantage in most cases of the level differences caused by tides). Forthe sake of simplicity, it has been depicted with a single storage basinor tank, assuming that level differences of tides, rivers or rainwaternetworks are exploited, and that therefore they are later dischargedback into the sea, but obviously if other exploitations (supply,sanitation, industrial networks, etc) are combined, a basin or tank foreach fluid that must be returned to a different place must be made

12) finally, if in the described pressure there is a residual pressureavailable after it has been used in the multiple fluid pumping useswhich may be necessary, there is obviously always the possibility ofusing it to centrifuge the fluid in question and producing electricpower. Furthermore, by inserting SCPEs again, the execution andmaintenance costs as well as the yield of the plants can be considerablyimproved, as has been described in point 2 above

There is a large variety of arrangements of SCPEs, as has been set forthabove. For the sake of simplicity, single exchangers with parallel lineshave been depicted in all the figures, but in each application theoptimal arrangement thereof will be chosen depending on the designparameters of the installation.

1-21. (canceled)
 22. A split-chamber pressure exchanger (SCPE) in whichthe available energy in a continuous flow of a pressurized fluid istransmitted to a fluid to be pressurized, comprising a plurality ofchambers in which pressure exchange occurs, said chambers in fluidcommunication with each other through a plurality of rigidly attacheddiscs or pistons, such that any contact between the pressurized fluidand the fluid to be pressurized is eliminated, said discs or pistonsadapted to allow the cross sections of the chambers corresponding toboth fluids to change.
 23. An SCPE according to claim 22, furthercomprising an auxiliary U-shaped tube which interconnects both discs orpistons, and which is telescopic at both sides of the “U”, said tubebeing rigidly supported by the base of the “U”, wherein the “U” isfilled with an incompressible fluid, such that when the pressurizedfluid enters its chamber, it not only presses its disc or piston todisplace the fluid to be pressurized, but also transmits part of itsenergy to the disc or piston of the other line to aid the fluid to bepressurized of the other line to displace the other alreadydepressurized fluid in said line and to overcome friction of the discsor pistons and their weight and the weight of the already depressurizedfluid if the assembly is vertical or angled.
 24. An SCPE according toclaim 22, wherein the chambers are curved or circular with the chambersarranged in a diametrically opposed manner, the chambers of eachcomprising different curvature radii, and attachment parts between thediscs or pistons is curved with radius and attached to a center of theSCPE by means of a ball-type joint, so as to allow increasing thepressure transmitted depending on distance of the chambers of bothfluids to the center without needing to change the cross sectionthereof, wherein the attachment parts between the discs or pistons arerigidly attached to one another to assure reverse line operation so asto simplify system control electronics, and to be able to displace thefluid which has transmitted its pressure in the SCPE, oncedepressurized, from the corresponding chambers thereof without a needfor auxiliary pumping for when the fluid to be pressurized enters undersubstantially low pressure.
 25. An SCPE according to claim 22, whereinthe available energy in a continuous flow of the pressurized fluid isexploited to transmit to the fluid to be pressurized such that thechamber of the pressurized fluid are split into several chambers, whichcan be used depending on available pressure of the fluid, by means of anelectronically controlled valve system, thus achieving transmittingsubstantially homogeneous pressure to the fluid to be pressurized toform a multistage SCPE.
 26. An SCPE according to claim 25, wherein bybeing provided with circular chambers and a reverse operation systembeing aided by means of the U-shaped tube for when the pressure at whichthe pressurized fluid must be returned after depressurizing is variable,and/or starting pressure of the fluid to be pressurized is variable,wherein programming a control system so that stages which must startoperating depending on the pressures are adjusted.
 27. An SCPE accordingto claim 22, further comprising a variable section in at least one ofthe chambers and pistons.
 28. An SCPE according to claim 27, wherein byproviding one of the chambers with an initial variable section span,during which the piston accelerates until reaching a certain speed whena straight span of the chamber is reached, and the speed is keptconstant since at that time the force exerted on the piston by thepressurized fluid is equal to the force exerted by the fluid to bepressurized on the piston plus the losses due to friction correspondingto the speed.
 29. An SCPE according to claim 27, wherein by providingone of the chambers with an initial span with a different section,during which the piston accelerates until reaching a certain speed whena straight span of the chamber is reached, and the speed is keptconstant since at that time the force exerted on the piston by thepressurized fluid is equal to the force exerted by the fluid to bepressurized on the piston plus losses due to friction corresponding tothe speed.
 30. A recovery system comprising the SCPE according to claim22 for recovering energy from brine in desalination plants by reverseosmosis, wherein contact between brine and pre-treated seawater isprevented and section ratio between the chambers is such that thepre-treated seawater is pressurized until a pressure necessary todirectly feed reverse osmosis filters without needing a booster pump.